1. Field of the Invention
The present invention relates to a semiconductor package. More specifically, the present invention discloses a non-ceramic image sensor semiconductor package having a vision chip and a transparent window supported by a castellation.
2. Description of the Prior Art
Image sensors are used in a wide variety of electronic devices. These electronic devices rely on highly reliable and low cost image sensor devices. However, conventional image sensor devices are prone to failure and are relatively expensive to manufacture.
The conventional device basically consists of a ceramic housing with electrical leads protruding through the sides of the ceramic housing. Once a chip has been attached inside the housing, a glass cover is glued to the top of the housing. The glass cover is essentially the same size as the ceramic housing.
The conventional device as described above, has several disadvantages. For example, the glass cover can easily separate from the ceramic package. As a result, the chip is exposed to the external environment thereby destroying the device. Another problem is that moisture can enter the package which causes condensation on the inside of the glass thus degrading the image capturing ability and quality of the chip. Furthermore, the ceramic material used in the conventional device is relatively expensive.
Therefore, there is need for an improved image sensor semiconductor package with improved moisture resistance, lower cost, and higher reliability.
To achieve these and other advantages and in order to overcome the disadvantages of the conventional device in accordance with the purpose of the invention as embodied and broadly described herein, the present invention provides a non-ceramic image sensor semiconductor package having a vision chip and transparent window with improved moisture resistance, higher reliability, and lower production cost.
A concern with image sensor semiconductor devices is moisture resistance. If moisture is allowed to enter the device, condensation will form on the glass window, semiconductor chip, or vision chip active area. Conventional devices are susceptible to such moisture problems. However, in the present invention, the flatness of the substrate, the similarity of the materials and properties, and the greater adhesion between materials, provides for a highly reliable and moisture resistant image sensor device.
In addition, the ceramic material of the conventional device is more expensive than the organic material utilized in the image sensor semiconductor device of the present invention. Therefore, an advantage of the present invention is the benefit of reduced production cost.
Conventional ceramic image sensor devices have several disadvantages. For example, the ceramic material used in producing the device is relatively expensive. In addition, moisture can enter the device causing condensation to form inside the part thus degrading the image sensing performance of the device. Furthermore, the glass cover can easily separate from the ceramic package as it is only held onto the ceramic package with glue. As a result, the chip is exposed to the external environment thereby destroying the device.
However, the present invention provides a non-ceramic image sensor semiconductor package with improved moisture resistance, lower cost, and higher reliability.
The non-ceramic image sensor semiconductor device comprises a multi-layer resin mask organic substrate, a semiconductor chip with a vision chip active area, conductive wires, a castellation, a transparent window, and encapsulant.
The multi-layer resin mask organic substrate is a substrate comprising a resin mask material and a resin substrate material of the same material. Utilizing the same materials allows the substrate to be extremely flat. The circuit traces of the resin mask in the substrate material are even, thus providing a very flat substrate surface. Therefore, there is better placement of the semiconductor chip and greater adhesion between the semiconductor chip and the substrate.
In contrast, other types of substrates are often inferior as the resultant substrate is not flat. In these substrates, the mask material is raised slightly above the substrate material, making the face of the substrate uneven and not flat. As a result, in integrated circuit using these substrates, properties such as adhesion between the semiconductor chip and the substrate, are inferior.
The semiconductor chip is bonded, for example, adhesively bonded, to the multi-layer resin mask organic substrate by means of an adhesive.
The semiconductor chip comprises a vision chip active area. The vision chip may be contained as a part of the semiconductor chip or separate. The vision chip can be a complementary metal oxide semiconductor (CMOS) or a charge-coupled device (CCD) vision chip.
A plurality of conductive means are bonded or attached between conductive contacts or traces on the active side of the semiconductor chip and the multi-layer resin mask organic substrate. The conductive means comprise, for example, gold bonding wires.
The conductive means are utilized to create selective electrical connections between conductive contacts, pads, or traces on the semiconductor chip and the multi-layer resin mask organic substrate.
Castellations are formed to create risers surrounding the semiconductor chip. The height of the castellation can be made to a desired height so that proper clearance of the semiconductor chip and the vision chip active area and the glass window. is achieved. The castellations are made of, for example, substrate material or elastomer and may be silicon coated. An advantage of the present invention is that by using a material for the castellations that is the same or similar to the material of the organic substrate, the physical properties of the two will be similar thereby making the adhesion stronger between the organic substrate and the castellations.
After the castellation has been formed, a transparent window is placed on the top of the castellation. The transparent window comprises, for example, a boro-silicate glass window.
A liquid encapsulant is formed to cover desired areas and portions of the multi-layer resin mask organic substrate, castellation, and the glass window. Preferably, the encapsulant does not cover more of the glass window than is supported by the castellations.
The encapsulant is formed by, for example, printing. The encapsulant adhesively fixes and protectively seals the non-ceramic image sensor semiconductor package thereby shielding the semiconductor chip and vision chip active area from the external environment. Additionally, since the substrate is a resin mask organic substrate and very flat, the adhesion between the substrate and the encapsulant is very strong.
In addition, the transparent window may be placed on the castellation in the same production process as the encapsulant. In this way, additional processing steps are eliminated and production costs are lowered.
Therefore, the present invention provides a non-ceramic image sensor semiconductor package having a vision chip and grass window with improved moisture resistance, lower cost, and higher reliability.
These and other objectives of the present invention will become obvious to those of ordinary skill in the art after reading the following detailed description of preferred embodiments.
It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the invention as claimed.